Insecticide spray material and method of making the same



Patented F eb. 23, 1943 INSECTICIDE SPRAY MATERIAL AND METHOD OF MAKINGTHE SAME Robert B. Arnold, Stonewall Courts, Va., assignor to TobaccoBy-Products and Chemical Corporation, Louisville, Ky., a corporation ofDelaware No Drawing. Application June 14, 1940,

v Serial No. 340,523

8 Claims. (Cl. 167-33) This invention relates to a spray material and toa. process of making the same.

In my application, Serial No. 186,301, filed Jan.

22, 1938, for Insecticides and process of making the same, Patent No.2,219,287, I have disclosed a spray material which comprises a series ofin-. gradients, one of which is a complex solid polysilicate of aninsecticidal alkaloid selected from the group consisting of nicotine,nornicotine, anabasine, on which solid there is adsorbed an excess of awater-soluble, volatilizable salt of the same alkaloid. With thispolysilicate of alkaloid.

surcharged with a salt of the same alkaloid, there is mixed a sufficientquantity of raw, that is, unacted upon, complex polysilicate, which,when the mixture is added to water in the spray tank, will react withthe surcharge of alkaloid salt 'to produce more polysilicate of thealkaloid. This results in a very effective stomach poison for chewinginsects. I have discovered that the same complex polysilicate of analkaloidof the group named hereinbefore, and carrying a surcharge ofalkaloid salt, may be used, without the addition of the said rawpolysilicate, as'a spray'material for making a combination spray. Theresulting product may be prepared at the factory and shipped to aconsumer for use in making an insecticide spray which will beexceedingly effective not only asa stomach poison, .to protect a plantagainst chewing insects, but also as a contact poison to destroy'suckinginsects on said plant at the time of spraying. Also, I have discoveredthat while the complex polysilicate of an insecticidal alkaloid of thegroup named hereinbefore carrying a surcharge of salt of the namedalkaloid in volatilizable form will lose some of its lethal strengthwith lapse of time unless packaged in air-tight moisture-proofcontainers, it will when so packed retain substantially all its lethalstrength, and, furthermore, I have found that the rate of itsloss ofstrength is slow enough to allow such a spray material to be deliveredto a consumer, even in'non-hermetic packages, and

still be valuable as a spray material, where the' tion in part of mysaid application Serial No.

186,301, hereinbefore named, comprises a solid comminutedwater-insoluble salt of an insecticidal alkaloid selected from the groupconsisting of nicotine, nornicotine, anabasine, surcharged withasubstantial proportion of a water-soluble the whole product being adry,finely comminuted material in discrete particles, which may be V pouredinto containers, and may be made to carry 'a relative y high, totalproportion of the insecticidal alkaloid. In the best embodiment of theinvention thealkaloid which is fixed in chemical combination with thesaid insoluble salt is identical with that in the water-solublevolatilizable -salt in dry form, which is carried by the discreteparticles of the said insoluble salt.

The invention also includes the process of making the spray material, anessential feature of which consists in contacting an adsorbent materialhaving suitable base-exchange properties with a water-soluble salt of aninsecticidal alkaloid selected from the group consisting of nicotine,nornicotine, anabasine, in the presence of a restricted amount of water,the proportion of alkaloid salt-being in substantial excess of thatwhich would supply alkaloid to satisfy the baseexchange properties ofthe said adsorbentmaterial, maintaining such contact of the saidingredients for such time and at such temperatures that thebase-exchange reaction between the adsorbent material and the alkaloidwill proceed to completion of the base-exchange reaction, that is, tothe point where the base-exchange material has chemically combined withthe maximum amount of alkaloid it will take in chemical combination, andthereafter heating the product to drive off all or substantially all themoisture which was present during the reaction. Durin this dryingoperation, which should be carried out with continuous mixing, theexcess salt of the al-- kaloid gradually takes a jelly-like orgelatinous form, coating the discrete particles of the solid adsorbentmaterial and as the heating proceeds will be finally adsorbed by suchparticles. The dried material, which may be somewhat lumpy, is groundand graded as by air-separation or sifting, so that the finished productis a substantially dry powder whose particles are non-adherent, and willflow readily, thus making handling of the material by chutes orconveyers very easy. V

It has been found that a complex polysilicate which has base-exchangeproperties is particularly suitable for carrying out the presentinvention, and such a material may be found in the general class of rawmaterials known as bentonites, which class, however, includes somematerials not so satisfactory for applicants purpose.

It has been found that certain Wyoming hen-- tonites known on the marketas Volclay or Wilkinite and some California bentonites known as saltofan alkaloid selected from the said group, Filtrol and Stay-up" areexcellent for carrying out the present invention. These satisfactorybentonites may be classified as complex polyalumino-silicates havingbase-exchange proper ties. (Sometimes the aluminum is replaced in partby trivalent iron.)

Such silicates hold in combination divalent and monovalent metals, forexample, calcium, magnesium, sodium and sometimes potassium, and ingeneral the alkaloid replaces part of such divalent or monovalent metalsin the base-exchange reaction and thereby enters into chemicalcombination with the poly-alumino- (or ferroor alu mino-ferro) silicate.

When using the best types of complex polysilicates above mentioned, toform a chemical combination with the alkaloid selected, it will be foundthat the resultant product gives a durable alkaloid combination fromwhich the chemically combined alkaloid will not be dissolved out bywater, nor will the alkaloid, such as nicotine,

nornicotine, or anabasine readily escape from theto say, when the saltis in' solution in water, as

the water evaporates, a part of the alkaloid will be set free in gaseousor vapor form. In usual practice the nicotine salts are employed, and ofthese nicotine sulphate is more readily available and most economical.The usual preparation of nicotine sulphate has about 40% nicotinestrength and is accompanied by about 40% water. About one-half itsnicotine mayvolatilize, but the remainder is retained.

It is to be understood that an important feature of the product of thepresent invention is its concentrated insecticidal strength. Forexample, it is practical by this invention to produce a nicotine spraymaterial having as high as about 14% to 18% nicotine strength, which, aswell known to those skilled in the art, is much above the nicotinestrength of prior dry powdered spray products containing nicotine. Ithas been found in practice that about 8 to 10% nicotine is about thelimit of strength for the complex polysilicate of nicotine, andapparently the highest concentration per unit weight of the finalproduct is attained when the adsorbed nicotine salt on the solidpolysilicate of nicotine carries about the same percentage of nicotineas exists in chemical combination with the said solid polysilicate,namely about 8%.

However, it has been found in practice that the use of too great asurcharge of nicotine salt on the solid polysilicate particles is likelyto result in a product which may cake or become lumpy when standing,even if kept in hermetically sealed packages. This difliculty is notencountered if the amount of nicotine salt used in making the product isnot more than that necessary to give there is not only no advantage inusing too small a proportion of excess alkaloid salt in making the spraymaterial, but a positive disadvantage, because not only does the lethalcontact action against sucking insects become too weak for practicalpurposes, but the process itself is afiected for the reason that thebase-exchange action between the polysilicate and theakaloid'saltproceeds more slowly as the excess amount of salt isreduced. In other words, mass action is to be considered in connectionwith base-exchangephenomena, wherefore the greater the amount ofalkaloid salt present, the more rapid the baseexchange action, andconversely the less the amount of alkaloid salt present the slower thesaid action.

While the proportions of the ingredients may be varied withinconsiderable limits, it has been found that the proportions hereinaftergiven are particularly satisfactory in order 'to provide a spraymaterial having a sufllciently high concentration of nicotine forpractical purposes and at the same time free from the disadvantages ofcaking or forming lumps during storage. While if exposed to theatmosphere it may lose some of its insecticidal power, it loses itsstrength relatively slowly so that it may be kept for a reasonable timewithout too great a loss of its insecticidal power.

In order to make the product, a suitable bentonite having the requiredcharacteristics hereinbefore pointed out is suitably comminuted andgraded, as by air-separationor sifting, to remove all particles whichwill not pass a screen of about mesh. Of course, if a finer product isdesired a finer mesh may be employed. The powdered material asordinarily obtained will contain about 7% moisture. If it contains morethan this it may be partlydried to the point where its moisture contentis about 7%. To such a material, nicotine sulphate of 40% nicotinestrength and containing about 40% water is added in considerable excess,as indicated by the proportions hereinafter given. After thoroughlymixing the materials as by grinding in a ball mill or stirring for tenminutes, a resultant product is obtained which is not a wet slurry, butonly slightly damp material and hence may be readily handled byconveyers or chutes and is in excellent condition to be passed into adrier. In the drier it is subjected to a temperature ranging about F. to220 F. and is retained in such drier until substantially all the freemoisture contained in the bentonite and in the nicotine sulphate hasbeen driven oil. The resultant product is the desired spray material.The relative proportions by weight of the materials at the beginning andat the end of the process are as follows:

The finished spray material will contain theoretically 15 nicotineofwhich about 8% is generally combined with the bentonite and theremainder is in the form of nicotine sulphate which has been adsorbed bythe bentonite and has been dried so as to be free from any stickiness.As the excess nicotine sulphate loses its water during the dryingoperation it gradually passes into the form of a jelly, adheres to andis adsorbed by the particles of'bentonite powder,

until finally the nicotine sulphate has been thoroughly dried and is nolonger sticky. Since in this drying operation, some lumps will beformed, the dried product is 'run through a suitable grinder and may begraded either by airsuspension methods or sifting. The spray material inits finished form is a finely comminuted dry product which can bereadily poured into and out of suitable packages and which will lose itsinsecticidal value relatively slowly. If charged into suitablehermetically sealed containers it maybe kept iormany months withoutappreciable loss of nicotine strength.

When it is to be used as a spray, it may be mixed with water inthe usualspray tank in such proportions as are necessary to give the requiredstrength of nicotine in the liquid spray. Generally the proportions arethree pounds of the spray material to 100' gallons of water in the spraytank.

- When the spray is applied to a plant, about one-half the nicotine inthe spray is in the watersoluble salt and serves as a contact poison tokill sucking insects, while the remainder of the nicotine, which is inchemical combination with the bentonite, remains on the plant to act asa stomach poison to kill chewing insects.

In normal practice such a combination spray is desirable because oneapplication of spray destroys the sucking insects and leaves a residueto protect the plant for a time against chewing insects which may thenbethere or come somewhat later while the spray deposit remains on theplant. However. it sometimes happens that a plague of sucking insectsmake it desirable to convert some or all of the nicotine which isnonvolatile and insoluble because held in chemical combination with thebentonite, into a soluble form which will be dissolved in the water ofthe spray, so that, when the latter contacts with sucking insects itwill destroy them.

It is an important advantage of the present spray material, that theaddition of some lime to the water in the tank will break up thechemical combination of the bentonite and nicotine, because lime willdisplace the nicotine chemically held by the bentonite. in proportion tothe amount of it added to the water in the spray tank, thereby renderingsoluble a proportionate amount of nicotine.

Furthermore, if it be desired to convert the spray to one which iswholly a stomach poison spray, it is only necessary to add some raw,that is,'unacted upon, base-exchange material, such as bentonite of theclass mentioned, to the spray tank mixture, whereupon the nicotine inthe water-soluble salt will enter into base-exchange reaction with theraw bentonite, and the final product is a water-insoluble salt ofnicotine, dispersed in the water by agitation, and when sprayed on aplant, serves only as a stomach poison, such a stomach poison spraymaterial being the subject-matter of my said application.

It is to be understood that in using the spray materials of the typesillustrated by the examples given hereinbefore, there will generally beused some so-called spreader material added It is material in suchproportion as to give the correct percentage of spreader in the spraytank.

It has been found that by applicant's process it is possible in regularcommercial practice to provide a spray material carrying from 8 to 10%of nicotine in insoluble form and from 6 to 8% in water-soluble form,thereby providing a dry,

solid, comminuted spray material which on mere admixture will be highlyeffective asa combination spray.

What is claimed is:

1. A preformed spray composition suitable for use in making aninsecticidal aqueous spray, consisting of a solid dry comminuted,polysilicate of metal selected from the group consisting of aluminum,iron in trivalent form, said polysilicate having in chemical combinationan insecticidal alkaloid selected from the group consisting of nicotine,nornicotine, anabasine, and also carrying a surcharge consisting of arelatively large amount of water-soluble salt of the same alkaloid insubstantially dry form adsorbed on the polysilicate.

2. A preformed spray composition suitable for use in making an aqueousinsecticidal spray, consisting of a solid dry comminuted polysilicate ofmetal selected from the group consisting of aluminum, iron in trivalentform, said polysilicate having in chemical combination an insecticidalalkaloid selected from the group consisting of nicotine, nornicotine,anabasine and also carrying a surcharge consisting of an amount ofwater-soluble salt of the same alkaloid in substantially'dry formadsorbed on the polysilicate, the alkaloid in the water-soluble saltbeing in rela tively high ratio to the alkaloid in the insolublepolysilicate.

3. A preformed spray composition for use in making an aqueousinsecticidal spray consisting of a solid, comminuted, insolublepolysilicate of metal selected from the group consisting of aluminum,iron in trivalent form, said polysilicate having in chemical combinationabout 8 to 10% of an insecticidal alkaloid selected from the groupconsisting of nicotine, nornicotine, anabasine, and also carrying asurcharge adsorbed on the polysilicate and consisting of such an amountof water-soluble salt of the same alkaloid as will provide about 6 to 8%of the alkaloid in the spray composition, whereby the spray compositionwill carry from 14 to 18% of alkaloid.

4. A preformed spray composition for use in making an aqueousinsecticidal spray consisting of a solid, comminuted, insoluble complexpolysilicate of nicotine and of metal selected from the group consistingof aluminum, iron in trivalent an advantage of the invention that solidand dry spreaders such as the lauryl alcohol compounds known assulphates and sulphonates, and particularly such a compound now sold onthe mar- .ket as Orvus, may be packaged with the spray form, saidnicotine polysilicate carrying an adherent surcharge of nicotinesulphate, adsorbed on the polysilicate and in such an amount as to be ina relatively high ratio to the combined alkaloid.

5, The process of producing a solid, drycombination spray material,suitable for use in making an aqueous insecticidal spray, whichcomprises contacting, in the presence of a limited amount of water, acomminuted solid polysilicate material having base-exchange propertiesand adsorptive properties with a salt of an alkaloid selected from thegroup consisting of, nicotine, nornicotine, anabasine, the amount ofsuch salt being suilicient to provide alkaloid in substantial excess ofthat necessary to satisfy the base exto insure the adsorption of theexcess of unreacted salt by the said solid material.

6. The process of producing an insecticidal spray material whichcomprises contacting solid polysilicate having base-exchange andadsorptive properties in the presence of a limited amount'of water"insuflicient to form a slurry, with a nicotine salt in amount providingnicotine in substantial excess of that necessary to satisfy thebase-exchange properties of the polysilicate, and then heating theproducts of the reaction to insure the adsorption of the excess ofnicotine salt by the polysilicate.

7. The process of making a solid, dry nicotine spray material carrying arelatively high nicotine content, which consists in contacting in thepresence of a limited amount of water insuflicient to form a slurry, asolid, comminuted polysilicate having base-exchange and adsorptiveproperties, with an amount of nicotine sulphate in large excess of thatnecessary to provide nicotine suiiicient to satisfy the base-exchangeproperties of the polysilicate. then subjecting the reaction products toa temperature of about 180 to 220 F. for a time suflicient to drive offsubstantially all the water and cause the adsorption and drying of theexcess of nicotine sulphate by the polysilicate, and finally grindingand grading the material.

8. The process of making a dry concentrated nicotine spray materialwhich on mere admixture with water will form an efficient combinationinsecticidal spray which consists in intimately mixing about 68 per centof finely comminuted polysilicate of the bentonite type havingbase-exchange and adsorptive properties for nicotine and containingabout seven per cent water, with about 32 per cent of nicotine sulphatehaving about per cent nicotine and about 40 per cent water, heating theresultant damp product in a drier at a temperature of between and 220 F.for a sufflcient time to drive off substantially all the water, andfinally grinding and grading the product.

ROBERT B. ARNOLD.

